友好地

Here, '友好' (friendly) is used as an adverb to describe how she smiled. '友善' is an adjective, '友谊' is friendship (noun), and '友人' is a friend (noun).

The context implies the teacher helps with warmth and friendliness. '热情' (warm, friendly) fits best as an adverb here. '热烈' means enthusiastic (for applause), '热心' means warm-hearted, '热气' means heat.

The word '高兴地' (happily) describes the manner of greeting. While '高兴' means happy, the adverbial '地' is needed to modify the verb '打招呼' (greet).

Here, '友好' (friendly) describes the new neighbors. '友爱' means brotherly love, '友情' means friendship, and '友善' is a synonym for friendly but '友好' is also very common in this context.

The phrase suggests he introduced the city with enthusiasm and helpfulness. '热心' (warm-hearted, enthusiastic) best fits this meaning. '详细' means detailed, '仔细' means careful, '耐心' means patient.

'亲切' (kind, cordial) implies treating everyone with warmth and friendliness. '亲密' means intimate, '亲热' means affectionate, and '亲近' means to be close to.